void main(List<String> args) {
  // 1. 算术运算
  double a = 100;
  double b = 3;
  print(a + b);
  print(a - b);
  print(a * b);
  print(a / b);
  print(a % b);
  // 除完取整
  print(a ~/ b);

  print('\n2. 赋值运算');

  // 2. 赋值运算
  double count = 10;
  print(count += 10);
  print(count -= 10);
  print(count *= 10);
  // 只有double类型支持/=
  print(count /= 10);
  print(++count);
  print(--count);

  print('\n3. 比较运算');

  // 3. 比较运算
  int x = 10;
  int y = 20;
  print(x > y);
  print(false == 0);
  print(false != 0);

  print('\n4. 逻辑运算');

  // 4. 逻辑运算
  int age = 36;
  int year = 15;
  print(age < 35 && year > 10);
}
